Joint custody and shared parenting have been studied for more than a
quarter-century, with the majority of studies indicating significant benefits
for children. About a third of existing studies show no difference
between joint and sole custody for children's adjustment to divorce. The
critical factor appears to be conflict between parents. When parents
cooperate and minimize conflict, children do better with shared parenting.
If there is significant conflict between parents, however, shared parenting
provides no benefits and children do no better (and no worse) than they do
in sole custody. This section summarizes some of the studies published
in the past decade.

Joint Legal Custody

Joint legal custody has been consistently linked with more parental
involvement, higher child support compliance, and less conflict between parents.
Until recently, however, it was not clear whether these benefits occurred
as a result of joint legal custody, or simply because more cooperative
parents chose joint custody in the first place. The 1997 study by Seltzer
provides strong evidence for a cause and effect relationship between joint
legal custody and the benefits associated with it.

Seltzer used data from the National Survey of Families and Households, a
survey of over 13,000 families that collected data in two waves, 1987-88
and 1992-94. Because the study included data on the quality of family
relationships, it was possible to study the effects of joint legal custody
while controlling from pre-separation family relationships by analyzing data
on families that had separated between the survey waves.

Seltzer concluded that "Controlling for the quality of family relationships
before separation and socioeconomic status, fathers with joint legal custody
see their children more frequently, have more overnight visits, and pay more
child support than fathers in families in which mothers have sole legal custody."
She suggests that joint legal custody helps reduce visitation denial: "By
clarifying that divorced fathers are 'by law' still fathers, parents'
negotiations about fathers' participation in child rearing after divorce
may shift from trying to resolve whether fathers will be involved
in child rearing to the matter of how fathers will be involved." [emphasis
in original]

Joint Physical Custody

A study of 517 families with children ranging in age from 10.5 years to 18
years, across a four and a half year period. Measures were: assessed depression,
deviance, school effort, and school grades. Children in shared parenting
arrangements were found to have better adjustment on these measures than
those in sole custody.

This study included "forty boys and girls, ages 8 to 12, in attendance at
selected private secular and parochial schools in a large Southwestern
metropolitan area participated, along with their middle to upper-class parents."
The study compared adjustment of children in joint and sole physical custody,
controlling for level of conflict between parents, to determine if parental
conflict would be more detrimental to children in joint or sole custody.
The author summarized findings as follows: "Overall, no significant
difference between joint and sole physical custody groups was found."

This study compared 21 joint custody and 21 maternal custody families, with
children between the ages of 4-15.

Results showed that misbehavior and "acting out" were more common among sole
custody children: "A multiple regression analysis of these data found children
in joint custody families had fewer behavioral adjustment problems with
externalizing behavior than children in mother custody families." "Regardless
of custody arrangement, parents with low self esteem were more likely to
have children with behavioral adjustment problems when predicting the child's
overall behavioral adjustment and internalized behavior."

Ilfeld, Holly Zingale "Children's perceptions of their relationship with
their fathers in three family constellations: mother sole custody, joint
custody and intact families" Doctoral dissertation, U. of California,
Davis 1989

This study evaluated children's perceptions of their fathers at least four
years post-divorce, comparing joint custody, sole custody and intact families.
The subjects were 43 latency-age children: 11 from maternal custody families,
14 from joint custody families and 18 controls from intact homes.

Results: "There was a significant difference in the perceptions of children
in sole and joint custody. Joint custody children reported spending more
time with their fathers in childcentered activities, activities which were
considered pleasurable and important to children. " And: "No differences
were found as a function of custody arrangements in children's perceptions
of emotional closeness to the father, acceptance by the father, or fathers's
potency or activity. "

Lerman, Isabel A. "Adjustment of latency age children in joint and single
custody arrangements" California School of Professional Psychology, San
Diego, 1989

Results showed negative effects for sole custody: "Single custody subjects
evidenced greater self-hate and perceived more rejection from their fathers
than joint physical custody subjects." Conflict between parents was found
to be a significant factor, which may explain the better adjustment for joint
physical custody children: "Degree of interparental conflict was a significant
predictor of child self-hate. Higher conflict was associated with greater
self-hate; lower conflict was associated with lower self-hate." "Higher
father-child contact was associated with better adjustment, lower self-hate,
and lower perceived rejection from father; lower father-child contact was
associated with poorer adjustment, higher self-hate, and higher perceived
rejection from father. "

Extreme Situations

In situations with high levels of conflict, mental illness, or domestic
violence, joint physical custody is no better (and no worse) than sole
custody.

Surviving the Breakup, J. Wallerstein and J. Kelly;
Second Chances, J. Wallerstein and S. Blakeslee; and other publications.
Judith Wallerstein and colleagues have produced many publications on a 20+
year study of 184 families that had been referred to her clinic for therapy.
The parents were predominantly mentally ill, with approximately half the
men and half the women "moderately disturbed or frequently incapacitated
by disabling neuroses and addictions," including some who were "sometimes
suicidal." An additional 20% of the women and 15% of the men were categorized
as "severely disturbed." Approximately one third of the sample were considered
to have "adequate psychological functioning" before divorce. Although there
was a significant level of attrition, with families dropping out of the study
when problems were resolved, some conclusions emerged from the remaining
families. Children in joint custody situations did no better than those in
sole custody, indicating that parents must be reasonably psychologically
healthy for shared parenting to benefit children.